The invention relates to a flow meter comprising a fluid flow target which in use is disposed in a fluid flow path. Such flow meters are typically referred to as target flow meters.
Target flow meters operate on the principle that the drag force acting on a body due to fluid flow is related to the flow rate of the fluid. A previously considered target flow meter comprises a drag plate disposed within a fluid conduit and attached to a support member which extends to the outside of a conduit. The support member is pivotable and the force acting on the support member, causing it to turn it about the fulcrum, is measured. The flow meter is calibrated so that the force measured can be converted to a flow rate. Such a target meter is shown and described in section 3.2.7.3 of British Standard BS 7405.
Whilst such target flow meters are satisfactory for many applications, the reliability and accuracy may not be particularly good, and the resolution at lower flow rates may not as good as at higher flow rates since the force is proportional to the flow rate squared.
It is therefore desirable to provide an improved flow meter.